LU82558A1 - NON-AQUEOUS BATTERY - Google Patents

Description

The present invention relates to a non-aqueous cell comprising an active metal anode, a cathode collector, a separator arranged between the cathode collector and the anode and separating them from each other, an active liquid cathode-electrolyte, the surface of the separator facing the anode being coated with a vinyl polymer film.

The production of high energy batteries requires, among other things, the compatibility of an electrolyte endowed with advantageous electrochemical properties with highly reactive anode materials such as lithium, etc. The use of aqueous electrolytes is excluded from these systems, since the anode materials are sufficiently active to react chemically with water. It was therefore necessary, in order to achieve the high energy density which can be obtained by means of these very reactive anodes, to direct research towards non-aqueous electrolyte systems.

The term "nonaqueous electrolyte" used herein refers to an electrolyte which is composed of a body such as, for example, a metal salt or a complex salt of elements of Group IA, Group IIA, of Group IIIA or Group VA of the Periodic Table, dissolved in a suitable non-aqueous solvent. The expression "Periodic Table 25" used in this memo designates the Periodic Table of the Elements reproduced on the third cover page of the book entitled Handbook of Chemistry and Physics, 48th edition, The Chemical Rubber Co., Cleveland,

Ohio, 1967-1968.

Many dissolved bodies are known and the use of many has been suggested, but the choice of a suitable solvent has been particularly problematic. The ideal battery electrolyte would include a pair formed of a solvent and a dissolved body having a wide range of existence in the liquid state, high ionic conductivity and great stability. A wide range of existence in the liquid state, i.e. a high boiling point and a low freezing point, is essential if the battery is to operate at temperatures other than ambient temperatures. normal. High ionic conductivity is necessary if the battery is to have a large nominal power. Stability 5 is essential for the materials constituting the electrodes, the materials constituting the battery and the products of the reaction of the battery, in order to obtain a long shelf life when the battery is used in a primary or secondary battery.

It has been revealed in recent literature that certain materials are capable of behaving both as an electrolyte carrier, i.e. as a solvent for the electrolytic salt, and as an active cathode for an electrochemical cell not aqueous. U.S. Patent Nos. 3,475,226, 3,567,515 and 3,578,500 each disclose that liquid sulfur dioxide or solutions of sulfur dioxide and a cosolvent assume this double function in nonaqueous electrochemical cells. Although these solutions assume their double function, they are not without their certain drawbacks in service. Sulfur dioxide is always present and, since it is gaseous at ordinary temperatures, it must be retained in the cell as a liquid under pressure or in the state dissolved in a liquid solvent. Handling and packaging problems are caused if sulfur dioxide is used alone, and an additional component and an additional assembly step are required if sulfur dioxide is to be dissolved in a liquid solvent. As noted above, a wide range in the liquid state covering normal ambient temperatures is a desirable characteristic of an electrolyte solvent. Naturally, sulfur dioxide = is insufficient in this respect, at atmospheric pressure.

United States patent application No. 439,521 filed February 4, 1974 in the name of GE Blomgren et al. Discloses a non-aqueous electrochemical cell comprising an anode, a cathode collector and a cathode-electrolyte, the latter being a solution of an ion-conducting body "3, dissolved in an active cathode (depolarizer), said active cathode (depolarizer) being formed from a liquid oxyhalide of an element of Group V or Group VI of the Periodic Table. Although oxyhalides can be used effectively as components of a cathode-electrolyte in conjunction with an anode formed of an active metal, such as a lithium anode, to produce a correct battery having a high energy density, it has been observed that if the battery is kept for an extended period of about 3 days or more, passivation of the anode occurs and this results in unwanted voltage response delays at the start of discharge at the same time that a large internal resistance of the battery.

U.S. Patent No. 3,993,501 describes a means for minimizing or preventing unwanted voltage response delays at the start of discharge of nonaqueous batteries using an electrolyte cathode containing an oxyhalide by forming a coating consisting of a vinyl polymer film on the surface of the anode which is in contact with the cathode-electrolyte.

U.S. Patent Application No. 015,938 discloses a non-aqueous cell comprising an active metal anode such as lithium, a liquid cathode-electrolyte comprising a body dissolved in a solvent which is an oxyhalide of an element of Group V or Group VI of the Periodic Table, elementary sulfur or a sulfur compound being incorporated into the cathode-electrolyte so as to essentially eliminate the initial voltage delay of the battery during discharge.

One of the aims of the present invention is essentially to prevent the passivation of the active metal anode in liquid cathode-electrolyte batteries.

Another object of the invention is to provide a liquid cathode-electrolyte cell in which the surface of the separator facing the anode is coated with a film of vinyl polymer so as to essentially prevent passivation of the anode in active metal during storage and use of the battery.

- have 4 "

Another object of the invention is to produce a cathode-electrolyte cell in oxyhalide, in which the surface of the separator facing the active metal anode carries a coating formed by a thin film of vinyl polymer which adheres thereto, elemental sulfur or a sulfur compound being used in the cathode-electrolyte in accordance with the teaching given in the aforementioned patent application of the United States of America No. 015 938, so as to effectively prevent passivation of the anode made of active metal during storage and use of the battery.

Other characteristics and advantages of the present invention will emerge from the detailed description which follows.

The invention relates to a non-aqueous high energy density battery comprising an active metal anode; a cathode collector; a separator arranged between the anode and the cathode collector; an ion-conducting cathode-electrolyte solution formed from a body dissolved in an active liquid cathode (depolarizer) in the presence or absence of a reactive or non-reactive cosolvent; at least a portion of the surface of the separator, preferably the portion facing the anode, is coated with a vinyl polymer film so as to reduce the initial voltage response of the cell during discharge. Preferably, the vinyl coating carried by the separator should be used in a proportion in the range of about 0.7 to about 3.5 g / m of projected single-area, especially in the range of about 1.5 at about 1.8 g / m · An amount less than about 0.7 g / m is * 30 considered to be incapable of significantly reducing the duration of the voltage response upon initial discharge, while an amount greater than 2 approximately 3.5 g / m should cause cracking of the separator and prevent the flow of electrolyte.

The vinyl polymeric materials which can advantageously be used in the present invention are normally liquid vinyl polymers such as homopolymers of vinyl chloride or vinylidene or copolymers containing vinyl chloride or vinylidene chloride containing, under the copolymerized form, at least one of the monomers chosen from the group comprising vinyl esters, diacids, diacid diesters and monoacid diesters. The term "copolymers" is used herein to refer to mixed polymers as well as heteropolymers formed from two or more of two different monomers, polymerized together (see Concise Chemical and Technical Dictionary, 10 3rd edition, H. Bennett , editor, Chemical Publishing Co., 1974).

General examples of suitable copolymers include products of copolymerization of vinyl chloride with vinyl esters such as vinyl acetate, etc. ? products of copolymerization of vinyl chloride with diesters of diacids such as dibutyl maleate; products of copolymerization of vinyl chloride with vinyl esters such as vinyl acetate and diacids or mono-esters or diesters of diacids such as maleic acid, or dibutyl or monobutyl maleate. Representative examples include a copolymer of vinyl chloride and vinyl acetate containing 97% vinyl chloride and 3% vinyl acetate; a copolymer of vinyl chloride and vinyl acetate containing 86% vinyl chloride and 14% vinyl acetate; a copolymer of vinyl chloride, vinyl acetate and a diacid containing 86% vinyl chloride, 13% vinyl acetate and 1% maleic acid.

Advantageous vinyl polymers for use in the present invention are also described in U.S. Patent No. 4,141,870.

For the purposes of this memo and as described in an article entitled "Electrochemical Reactions In Batteries", Akiya Kozawa and RA Powers, published in the 35 Journal of Chemical Education, volume 49, pages 587 to 591, September 1972 edition, a cathode depolarizer is the reaction body of the cathode and, therefore, it is the material which undergoes electrochemical reduction at the cathode. The cathode collector is not an active reducible material and behaves like a current collector lined with an electronic conductor at the positive terminal (cathode) of a battery. In other words, the cathode collector is a site for the electrochemical reduction reaction of the active cathode material and of the electronic conductor connected to the cathode terminal of a battery.

Active liquid reducible cathode material (depolarizer) can be mixed with a conductive dissolved body which is a non-reactive material, but which is added to improve the conductivity of liquid active reducible cathode material, or this material can be mixed with a conductive dissolved body 15 and a reactive or non-reactive cosolvent. A reactive co-solvent is a co-solvent which has electrochemical activity and therefore behaves like an active cathode material, while a non-reactive co-solvent is a co-solvent which is electrochemically inactive and which, by 20 therefore, cannot behave like an active cathode.

The separator for use according to the invention must be chemically inert and insoluble in the liquid cathode-electrolyte and it must be porous so as to allow the liquid electrolyte to infiltrate through it and enter contact with the anode of the cell, thereby establishing an ion transfer path between the anode and the cathode. An advantageous separator for use in the present invention is a non-woven or woven glass fiber mat.

Any compatible solid material which is substantially endowed with electronic conductivity can be used as a cathode collector in the batteries of the present invention.

It is desirable that there is as large a surface contact as possible between the cathode-electrolyte and the collector. It is therefore preferable to use a porous collector, since it creates a large specific surface interface with the liquid cathode-electrolyte. The collector can be metallic and can be present in any physical form, for example in the form of a metallic film, a metallic cloth or a compressed powder.

Preferably, however, a compressed powder collector should be formed at least partially from a carbonaceous material or other material with a large specific surface.

The dissolved body can be a single or double salt which produces a solution with ionic conductivity when dissolved in the solvent. Preferred dissolved bodies are complexes of inorganic or organic Lewis acids and inorganic ionizable salts. The main conditions required for the salt, simple or complex, to be acceptable, lie in its compatibility with the solvent used and in its ability to give a solution which conducts ions. According to the Lewis concept or electronic concept of acids and bases, many substances which do not contain active hydrogen can behave like acids or acceptors of electronic doublets. The basic concept is presented in the chemical literature (see Journal of the Franklin Institute, volume 226 - July / December 1938, pages 293-313, G. N. Lewis).

A reaction mechanism which has been suggested in connection with the manner in which these complexes function in a solvent is described in detail in U.S. Patent No. 3,542,602, in which it is presumed that the complex salt or the double formed between Lewis acid and the ionizable salt gives an entity which is more stable than either of the components considered alone.

Examples of advantageous Lewis acids for use in the present invention include aluminum fluoride, aluminum bromide, aluminum chloride, antimony pentachloride, zirconium tetrachloride, phosphorus pentachloride, boron fluoride, boron chloride and boron bromide.

Ionizable salts which can be used in combination with Lewis acids include lithium fluoride 8, lithium chloride, lithium bromide, lithium sulfide, sodium fluoride, sodium chloride, sodium bromide , potassium fluoride, potassium chloride and potassium bromide.

It is obvious to those skilled in the art that the double salts formed between a Lewis acid and an inorganic ionizable salt can be used as such or that the individual components can be added to the solvent separately to form the salt or ions results in situ. An example of such a double salt is that which is formed by combining aluminum chloride with lithium chloride to give lithium aluminum tetrachloride.

In accordance with the present invention, a nonaqueous electrochemical system is produced comprising an active metal anode, a cathode collector, a separator disposed between the anode and the cathode collector and carrying on its surface facing the anode a coating formed by a vinyl polymer film, and a cathode-electrolyte, which comprises a body dissolved in an active reducible electrolytic solvent such as at least one oxyhalide of an element of Group V or Group VI of the Periodic Table and / or a halide of an element from Group IV, V or VI of the Periodic Table, in the presence or absence of a cosolvent. The active reducible solvent of the electrolyte plays the dual role of solvent for the electrolytic salt and of active cathode of the cell. The term "cathode-electrolyte" is used within the meaning of the present specification to designate electrolytes containing solvents which can assume this double function.

The use of one and the same component of the cell both as an electrolyte solvent and as an active cathode is a relatively recent progress, since it was expected that in the past it was generally considered that the two functions were necessarily independent and could not be assumed by the same subject. In order for an electrolyte solvent to function in a cell, it is necessary that it is at the same time in contact with the anode and 9 9, of the cathode so as to form between them a continuous ionic path. Consequently, it was generally accepted that the material constituting the active cathode should never come into direct contact with the anode and that is why it was considered that the two functions were mutually exclusive. However, it has recently been discovered that certain active cathode materials such as liquid oxyhalides do not chemically react to any appreciable extent with an active anode metal at the interface between the metal and the cathode material, thereby enabling this material = come into direct contact with the anode and act as an electrolyte support. Although the theory on which the inhibition of the direct chemical reaction is based is not fully understood at present and although it is not desired to be limited to any theory, it appears that a direct chemical reaction is inhibited, either by a high energy of activation of the reaction, or by the formation of a thin protective film on the surface of the anode. Any protective film on the surface of the anode should not be formed to a sufficient extent to result in a large increase in anode polarization.

Although active reducible liquid cathodes such as oxyhalides inhibit the direct reaction of anode surfaces of active metal to an extent sufficient to allow them to behave both as cathode material and as electrolyte carrier for nonaqueous batteries, they actually cause the formation of a surface film on the active metal anode during storage of the cell, in particular at high temperatures, this film being formed from a fairly dense layer of crystalline material. This critalline layer appears to cause passivation of the anode and this results in a voltage response delay upon initial discharge along with high internal resistance values of the battery in the range of 11 to 15 ohms for a normal type C battery.

10

The degree of anodic passivation can be measured by observing the time required for the closed circuit voltage of the stored cell to reach the desired operating voltage after the discharge has started. If this delay exceeds 20 seconds, the anodic passivation should be considered excessive for most applications. It has been observed, for example, in lithium oxyhalide batteries that after a charge has been applied to the terminals of the battery, the voltage of battery 10 drops immediately below the desired operating voltage, and then s rises at a speed which depends on the temperature, the thickness of the crystal layer and the electric charge.

The exact composition of this layer is not known. The thickness and density of the crystal layer as well as the dimensions and shape of the crystals vary, as can be seen, with the duration of the storage period as well as with the temperature during storage. ; for example, at low temperatures, a relatively small growth of the crystal layer is observed compared to the larger growth of the layer which is observed at high temperatures of about 70 ° C. It has also been observed that when oxyhalides such as thionyl chloride or sulfuryl are saturated with SO2 / and then placed in a lithium anode cell, a crystalline layer is rapidly formed on the surface of lithium thereby passivating this metal .

In accordance with the present invention, it has been found that passivation of the anode can be prevented by adhering a film layer of a vinyl polymer to at least a portion of the surface of the cell separator which is preferably rotated. towards the anode. The vinyl polymer film should adhere to the separator, remain stable in the liquid cathode-electrolyte, and should not significantly reduce the capacity of the cell during storage and discharge. In most cases, the presence of the polymer film can even increase the capacity of the battery during high speed discharge.

11

Although it is not desired to limit the invention to any theory, it seems that one of the reasons why vinyl polymers, such as polyvinyl chloride polymers, are stable in the cathode-electrolyte cell in oxy- Halide, for example the lithium oxyhalide battery, can be explained as follows: one of the recognized mechanisms of degradation of a vinyl chloride polymer is dehydrochlorination, i.e. the release of 'a chlorine atom and a hydrogen atom with the formation of 10 HCl. This process continues until the electronegativity of the remaining chlorine atoms on the polymer is compensated by the energy of conjugation (i.e. the formation of a double bond) in the polymer. The subsequent degradation is likely to occur by a free radical-generating mechanism, as follows: I I I 1 I I I I I! I I f I I I -HCl -C = C-C = C-C = C-C-C--} -C-C = C-C = C-C-C-C--} -C = C-C = C-C = C-C = C.

He * "He

Cl H \ ci ¥ l 20 (* denotes a free radical).

For most of the compounds which have shown interaction or interference with the degradation of polymers, the phenomenon can be explained by the formation of radicals of the types R ', RO *, R00 * and atomic chlorine. The reaction mechanism by which SO2CI2 is decomposed probably proceeds by the formation of a free radical, ie Cl * and S02C1 *, as described in the article entitled "The Mechanism of the Thermal Decomposition of Sulfuryl Chloride" by ZG Szabo and T. Bérces, Zeit, für Physikalische Chemie, 30 new series 12: 168-195 (1952). Thus, according to LeChatelier's principle (chemical equilibrium), the stability of vinyl chloride polymers can be improved in the environment such as that which predominates in oxyhalide-based systems. In other words, if the concentration of any of the degradation products increases, the reaction balance is shifted in favor of the original undegraded polymer.

The polymers which can be used in accordance with the invention must not be degraded or decomposed in the presence of the solvent used for the coating operation or the liquid cathode-electrolyte used in the cell? they must also be able to form a thin coating which can adhere to the separator.

5 Although the materials of the above group do not have all the characteristics mentioned, any person skilled in the art can easily choose those which have them by a simple test consisting in applying the material to the surface of a separator immersed in a cathode-10 liquid electrolyte. For example, polyethylene and polypropylene would not be suitable because they would decompose in liquid oxyhalide.

The vinyl polymer film can be applied to the surface of the separator by any conventional technique such as spraying, brushing, etc., in the presence or absence of a suitable liquid suspending medium such as 3. -pentanone, methylisobutyl ketone (MIBK), diisobutyl ketone (DIBK) and 2-pentanone. A suitable liquid suspending medium could be one of the oxyhalide solvents used in the stack, for example thionyl chloride (SOCI2) or sulfuryl chloride (SC ^ C ^). Thus, a vinyl polymer such as a copolymer of vinyl chloride and vinyl acetate (86% vinyl chloride and 14% vinyl acetate for a molecular weight of about 40,000) can be dissolved in thionyl chloride and the solution can then be applied to the surface of the separator, either by immersion of the latter in the solution, or by application with a brush or by spraying the solution on the surface of the separator. During the evaporation of the oxyhalide used as solvent, a thin film remains which adheres to the surface of the separator. For example, the separator could be easily coated by immersion in a 1% solution of vinyl acetate and vinyl chloride copolymer in 3-pentanone, then drying the separator at about 200 ° C for 1 minute. This not only has the effect of depositing a suitable layer of vinyl polymer on the surface of the separator, but also of improving the mechanical handling characteristics of the material constituting the separator. If necessary, a thin layer formed of a film of vinyl polymer could be applied by lamination to the separator, provided that intimate contact and adhesion to the separator can be obtained.

In the industrial production of batteries, it is much easier to coat the surface of the separator than the anode and, moreover, the mechanical handling characteristics of the separator are improved, which therefore facilitates its incorporation into the battery.

The concentration of the vinyl polymer in the liquid medium can vary between wide limits as long as this concentration is deposited on the separator as indicated above. When using a separator 15 having a porosity of about 50%, it has been observed that a suitable concentration of vinyl polymer is between about 0.5 and 3.0% by weight based on the weight of the liquid suspending medium. A concentration less than 0.5% by weight would probably be insufficient to form an effective film on the separator, while a concentration greater than 3.0% by weight would not provide any significant additional protection against passivation of the anode. metallic and could even lead to deterioration of the separator during handling.

The effective concentration range of the vinyl polymer 2 can vary between about 0.7 and about 3.5 g / m of apparent single-area and is preferably between 2 about 1.5 and about 1.8 g / m. A concentration of less than about 0.7 g / m 2 would be incapable of substantially preventing passivation of the active metal anode such as lithium,. 2 while a concentration greater than about 3.5 g / m would undesirably raise the internal resistance of the cell.

Advantageous oxyhalides to be used in accordance with the invention include sulfuryl chloride, thionyl chloride, phosphorus oxychloride, thionyl bromide, chromyl chloride, vanadyl tribromide and selenium oxychloride.

. 14

Advantageous organic cosolvents for use in the present invention include the following classes of compounds:

Trialkyl borates: for example trimethyl borate (CH3O) 3B (liquid range -29.3 at 67 ° C)

Tetraalkyl silicates: for example tetramethyl silicate (CH30) 4Si (boiling point 121 ° C)

Nitro-alkanes: for example nitromethane, CH3NO2 ‘(liquid range -17 to 100.8 ° C)

10 Alkylnitriles: for example acetonitrile, CH3CN

(liquid range -45 to 81.6 ° C)

Dialkylamides: for example dimethylformamide, HCON (CH3) 2 (liquid range -60.48 to 149 ° C) _Lactams: for example N-methylpyrrolidone, 15 CH2-CH2-CH2-CO-N-CH3 (liquid range -16 to 202 ° C) Tetraalkylureas: for example tetrametylurea, (CH3) 2N-CO-N (CH3) 2 (liquid range -1.2 at 166 ° C)

Esters of monocarboxylic acids: for example ethyl acetate (liquid range -83.6 to 77.06 ° C) 20 Ortho-esters î for example trimethyl orthoformate, HC (00113) 3 (boiling point 103 ° C )

Lactones: for example gamma-butyrolactone, CH2-CR2-CH2-0-éo (liquid range -42 to 206 ° C)

Dialkyl carbonates: for example dimethyl carbonate, OC (OCH3) 2 (liquid range 2 at 90 ° C)

Alkylene carbonates: for example propylene carbonate, CH (CH3) CH2-0-C0-0 (liquid range -48 to 242 ° C)

Monoethers: for example diethyl ether (liquid range -116 to 34.5 ° C), 30 Polyethers: for example 1,1- and 1,2-dimethoxyethane (respective liquid ranges -113.2 to 64 , 5 ° C and -58 to 83 ° C)

Cyclic ethers: for example tetrahydro-furan (liquid range -65 to 67 ° C); 1,3-dioxolane (liquid range -95 to 78 ° C)

Nitro-aromatic compounds: for example nitro-benzene (liquid range 5.7 to 210.8 ° C) 15

Aromatic carboxylic acid halides: for example benzoyl chloride (liquid range 0 to 197 ° C); benzoyl bromide (liquid range -24 to 218 ° C)

Aromatic sulfonic acid halides: for example benzenesulfonyl chloride (liquid range 14.5 to 251 ° C)

Dihalides of aromatic phosphonic acids: for example benzenephosphonyl dichloride (boiling point 258 ° C) 10 Dihalides of aromatic thiophosphonic acids: for example benzeneethiophosphonyl dichloride (boiling point 124 ° C under pressure of 0.67 kPa

Cyclic sulfones: for example sulfolane, CH2-CH2-CH2-CH2-S02 (melting point 22 ° C); 3-methyl-15 sulfolane (melting point -1 ° C)

Alkylsulfonic acid halides: for example methanesulfonyl chloride (boiling point 161 ° C)

Alkylcarboxylic acid halides, eg acetyl chloride (boiling range -112 to 50.9 ° C); acetyl bromide (liquid range -96 to 76 ° C); propionyl chloride (liquid range -94 to 806C).

Saturated heterocyclic compounds: for example tetrahydrothiophene (liquid range -96 to 121 ° C); 3-methyl-25 2-oxazolidone (melting point 15.9 ° C)

Acid halides, dialkylsulfamics: for example dimethylsulfamyl chloride (boiling point 80 ° C, 2.13 kPa)

Alkyl halosulfonates: for example. 30 ethyl chlorosulfonate (boiling point 151 ° C)

Halides of unsaturated heterocyclic carboxylic acids, for example 2-furoyl chloride (liquid range -2 to 173 ° C)

Penta-35 unsaturated heterocyclic compounds: for example 3,5-dimethylisoxazole (boiling point 140 ° C); 1-methylpyrrole (boiling point 114 ° C); 2,4-dimethylthiazole (boiling point 144 ° C); furan (liquid range -85.65 to 31.36 ° C) 16

Esters and / or halides of carboxy-diacids: for example ethyloxalyl chloride (boiling point 135 ° C)

Alkylsulfonic acid halides and 5 mixed carboxylic acid halides: for example chlorosulfonylacetyl chloride (boiling point 98 ° C under pressure of 1.33 kPa)

Dialkyl sulfoxides par e.g. dimethyl sulfoxide (liquid range 18.4 to 189 ° C) 10 Dialkyl sulfates: e.g. dimethyl sulfate (liquid range -31.75 to 188.5 ° C)

Dialkyl sulfites: for example dimethyl sulfite (boiling point 126 ° C)

Alkylene sulfites: for example ethylene glycol sulfite (liquid range -11 to 173 ° C)

Halogenated alkanes: for example methylene chloride (liquid range -95 to 40 ° C); 1,3-dichloropropane (liquid range -99.5 to 120.4 ° C).

Among the co-solvents indicated above, nitrobenzene is preferred; tetrahydrofuran; 1,3-dioxolane; 3-methyl-2-oxazolidone; propylene carbonate; γ-butyrolactone; sulfolane? ethylene glycol sulfite? dimethyl sulfite and benzoyl chloride. Among the preferred / best co-solvents are nitrobenzene, 3-methyl-2-oxazolidone; benzoyl chloride, dimethyl sulfite and ethylene glycol sulfite, because they are more chemically inert to the components of a battery and because they have wide ranges of existence in the liquid state , and in particular because. 30 that they allow a very efficient use of cathode materials.

It is also within the scope of the invention to use inorganic solvents such as liquid inorganic halides of elements from Groups IV, V and VI of the Periodic Table, for example selenium tetrafluoride (SeF 4), monobromide selenium (Se2Br2), thiophosphoryl chloride (PSCI3), thiophosphoryl bromide (PSBr3), vanadium pentafluoride (VF5), lead tetrachloride (PbCl4), titanium tetrachloride (TiCl ^), decafluoride sulfur (S2F <| q), tin bromide-trichloride (SnBrC ^), dibromide-tin dichloride (SnBr2Cl2), tribromide-tin chloride (SnBr ^ Cl), sulfur monochloride (S2C12) and sulfur dichloride (SC12). These halides, apart from the fact that they behave as a solvent for the electrolyte in nonaqueous batteries, can also assume the function of an active reducible cathode, thereby contributing to the total active reducible material contained therein. these batteries.

Useful anode materials are generally consumable metals and include aluminum, alkali metals, alkaline earth metals and alloys of alkali or alkaline earth metals with each other and with other metals . The term "alloy" used herein includes mixtures, liquid solutions such as lithium-magnesium and intermetallic compounds such as lithium mono-aluminide. The preferred anode materials are alkali metals such as lithium, sodium and potassium, and alkaline earth metals such as calcium.

In the preferred embodiment, in the choice of the particular oxyhalide for a given cell, according to the invention, the stability of the particular oxyhalide in the presence of the other components of the cell and the temperatures must also be considered. work the battery should work on. Therefore, one must choose an oxyhalide which is stable in the presence of. 30 other battery components.

In addition, if you want to make the electrolyte solution more viscous or turn it into a gel, you can add a gelling agent such as colloidal silica.

The present invention is illustrated by the following examples, given without limitation.

Example 1

Three batches of 1.21 cm diameter batteries are prepared using the following components: 18 0.45 g of lithium? a cathode collector obtained from 0.65 g of a mixture of 90% by weight of carbon black and 10% by weight of binder consisting of "Teflon" (registered trademark of a polytetrafluoroethylene); a separator formed from felted nonwoven glass fibers (type "934S" from the firm Mead Co.) in contact with the cathode collector? and 3 - 2.4 cm of a liquid solution of eathode-electrolyte consisting of 1 M LiAlCl4 in SOCl2 and containing lithium sulfide added up to its saturation point in solution.

The components are combined in stainless steel containers which are closed with lids in a conventional manner.

The above batteries are kept under variable conditions, then discharged across a 75 ohm resistor. The average discharge voltage after one second, for the three batteries in each batch, is shown in Table I below.

TABLE I

Lot of Battery Storage Conditions Batteries freshly 1 week to 1 month to 3 months to 25 * prepared 71 ° C 20 ° C 20 ° C 1 2 3

3.18 V 2.50 V 1.76 V 1.38 V

2

3.40 V 1.08 V 1.82 V 0.96 V

3

2.88 V 1.27 V 1.52 V 1.07 V

Three other batches of cells were prepared as indicated above, except that the separators, before being incorporated into the cell, were immersed in a 1% by weight solution of acetate copolymer. vinyl and vinyl chloride in 3-35 pentanone, then quickly dried by heating at about 200 ° C for 1 minute. The copolymer of vinyl acetate and of vinyl chloride was a product of the firm Union Carbide Corporation marketed under the designation "VYHH", comprising 86% by weight of vinyl chloride and 14% by weight of vinyl acetate. The separators carrying the vinyl polymer coating were mechanically easier to handle and incorporate into the batteries. The three batches of batteries were kept under variable conditions and then discharged across a 75 ohm resistor. The average voltage observed for the three batteries in each batch after one second is shown in Table II.

TABLE II

Lot of Storage Conditions ^ batteries Batteries in state 1 week to 1 month to 3 months to

fresh 71 ° C 20 ° C 20 ° C

4 3.21 V 1.50 V 2.18 V 1.53 V

15 5 3.39 V 1.50 V 2.00 V 1.87 V

6 3.01 V 1.25 V 1.96 V 1.72 V

As the results indicated above show, the cells comprising the separators which carry a vinyl polymer coating exhibited a greater average voltage after storage for 1 month and 3 months than cells comprising the separators without coating.

The batches of six batteries were then continuously discharged across a 75 ohm resistor after storage under variable conditions and the average numbers of ampere-hours (Ah) were calculated for the three batteries in each batch and are reproduced in Table III.

TABLE III

Lot of Battery Storage Conditions ____ 1 week at 71 ° C 1 month at 20 ° C 3 months at 20 ° C 1 2 3 4 5 6 0.48 Ah 0.57 Ah 0.51 Ah 2 0.49 Ah 0 , 65 Ah 0.56 Ah 3 35 3 0.52 Ah 0.57 Ah 0.59 Ah 4 0.62 Ah 0.63 Ah 0.63 Ah 5 0.55 Ah 0.57 Ah 0.63 Ah 6 0 .72 Ah 0.59 Ah 0.61 Ah 3 20

Example 2

Several other cells are produced as indicated in Example 1, with the difference that the solution used to coat the separators comprises a concentration of copolymer of vinyl acetate and vinyl chloride ("VYHïï") in 3-pentanone which varies from 0.5 to 3% by weight, as indicated in Table IV. Three batteries of each type, including three batteries, the separator of which has not been k coated, are stored under variable conditions, then 10 discharged across a 75 ohm resistor. The average voltage after one second and the average number of ampere-hours delivered are shown in Table IV.

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22. The quantity of vinyl retained on the separator after coating with the various vinyl solutions ranges from approximately 0.7 to 1.0 g / m2 of material constituting the separator for the 0.5% by weight solution of vinyl in the solvent. , 5 to about 3.5 g / m of separator for the 3% solution of vinyl in the solvent. Based on the weight of the separator (about 25 g / m), this should represent, respectively, about 2.8 to about 14% by weight of vinyl in the range of 0.5 to 3% of coating solution used.

10 Example 3

Several other stacks of the type from Example 1 were produced with some of the separators carrying 1% by weight of vinyl acetate and vinyl chloride copolymer in 3-pentanone. In addition, the lithium electrodes of some batteries have been replaced by electrodes of lithium aluminum alloy, each weighing 0.52 g and consisting of an alloy 85% by weight of lithium and 15% by weight of 'aluminum. Three representatives of each type of the various batteries were stored under various conditions and then discharged across a 75 ohm resistor. The average voltages after one second and the average numbers of ampere-hours delivered are shown in Table V below.

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Other cells were made as shown in Example 1, except that in each of these cells, 0.479 g of lithium sheet or 0.450 g of extruded lithium was used as the anode; the cathode collector consisted of 85% by weight of carbon black and 15% by weight of "Teflon"; the cathode-electrolyte solution consisted of 2.4 cm of 1 M LiAlCl4 in SO2Cl2 and contained lithium sulfide added to the saturation point of the solution? the separator carried a coating formed from a vinyl solution as indicated in * table VI. The batteries were stored under various conditions and then discharged across a 75 ohm resistor. The average voltages of the three batteries observed after one second and the average number of ampere-hours delivered are shown in Table VI. In battery pack No. 8, the separators, after being immersed in the solution, were dried at room temperature for 2 hours. In battery batch No. 9, the separators were dried for one minute at 175 ° C, while in battery batch No. 10, the separators were dried at 225 ° C for one minute.

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Claims (10)

27 "B" CLAIMS 1. A non-aqueous cell formed of an ion-conducting cathode-electrolyte solution comprising a body dissolved in an active liquid cathode; an active metal anode; a cathode collector; a separator placed between the anode and the cathode collector? at least a portion of the surface of the separator being coated with a vinyl polymer film. 2. Non-aqueous cell according to claim 1, characterized in that the vinyl polymer is chosen from homopolymers of vinyl chloride or of vinylidene chloride and of copolymers containing vinyl chloride or of vinylidene chloride, containing at least a copolymerized monomer selected from vinyl esters, diacids, diacid diesters and diacid monoesters. 3. Non-aqueous cell according to claim 1, characterized in that the vinyl polymer is chosen from copolymers of vinyl chloride and of vinyl acetate, copolymers of vinyl chloride, of vinyl acetate and of a diacid and vinyl chloride homopolymers. 4. Non-aqueous cell according to any one of the preceding claims, characterized in that the amount of vinyl polymer film on the separator ranges from approximately 0.7 to approximately 3.5 g and preferably from approximately 1.5 25 to 1.8 g / m2 of projected single-family area. 5. Non-aqueous cell according to any one of claims 1 to 3, characterized in that the cathode electrolyte contains a material chosen from lithium sulfide and sulfur monochloride and their mixtures. 6. A non-aqueous cell according to any one of claims 1 to 3, characterized in that the electrolyte cathode contains at least one liquid oxyhalide chosen from thionyl chloride, sulfuryl chloride, phosphorus oxychloride, thionyl bromide, chromyl chloride, vanadyl tribromide and selenium oxychloride, preferably thionyl chloride or sulfuryl chloride. 28 t Λ t 7. A non-aqueous cell according to any one of claims 1 to 3, characterized in that the anode is chosen from lithium, sodium, calcium, potassium and aluminum. 8. A non-aqueous cell according to claim 6, characterized in that the cathode-electrolyte contains an inorganic or organic cosolvent. 9. A non-aqueous cell according to claim 6, characterized in that the anode is lithium and the liquid oxy-10 halide is thionyl chloride or sulfuryl chloride. * 10. Non-aqueous cell according to any one of claims 1 to 3, characterized in that the dissolved body is a complex salt of a Lewis acid and an ionizable inorganic salt. 1